


Kissing 101

by LazyRainDancer



Category: Undertale (Video Game)
Genre: Alternate Universe - Underswap, No Smut, Other, Reader Is Not Chara, Reader Is Not Frisk, Reader is gender neutral, Reader teaches Sans how to kiss, Reader-Insert, Since this takes place in Underswap he goes by Sans rather than Blueberry, Tooth-Rotting Fluff, Underswap Sans isn't as innocent as he appears
Language: English
Status: Completed
Published: 2018-02-17
Updated: 2018-02-17
Packaged: 2019-03-19 17:57:21
Rating: Not Rated
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,100
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/13709658
Author URL: https://archiveofourown.org/users/LazyRainDancer/pseuds/LazyRainDancer
Summary: “Y/N! I WOULD LIKE FOR YOU TO TEACH ME HOW TO KISS!”Your gaze abruptly snaps up from looking at your phone, and you see Sans standing in front of you with his hands on his hips, wearing a determined expression.For a few seconds, all you do is gape. How did he go from working on designing new puzzles to wanting to learn how to kiss?!Your cute boyfriend wants to learn how to kiss, so he asks you for help. Of course, you're happy to oblige.





	Kissing 101

“Y/N! I WOULD LIKE FOR YOU TO TEACH ME HOW TO KISS!”

Your gaze abruptly snaps up from looking at your phone, and you see Sans standing in front of you with his hands on his hips, wearing a determined expression. 

For a few seconds, all you do is gape. How did he go from working on designing new puzzles to wanting to learn how to kiss?!

While you had been dating the skeleton for a few weeks now, the two of you had never actually kissed besides on the cheek or forehead. It was obvious that Sans didn’t have a lot of dating experience, so you decided to take things slow and go at his pace. You’ve always wanted to kiss him, but you wanted to wait until he was ready to initiate the contact.

With a quick shake of your head, you collect yourself and give your boyfriend a curious look. “I don’t mind, but what brought this up all of a sudden? I thought you wanted to work on your puzzles today.”

Sans moves to take a seat beside you on his rocket ship bed. His cheekbones now have a dark blue hue. “WHILE PUZZLES ARE IMPORTANT, YOU ARE MORE SO. I’VE ALWAYS WANTED TO KISS YOU, BUT I DIDN’T KNOW HOW SINCE I LACK LIPS. STILL, I DON’T WANT TO GIVE UP WITHOUT TRYING! I’M SURE THERE IS A WAY I CAN DO IT SO I CAN SHOW YOU JUST HOW MUCH I LOVE YOU!”

Your heart melts at his words. He truly is the sweetest boyfriend. With a warm smile, you lean down to kiss his cheekbone which makes him blush harder. “Even without kisses, you do a wonderful job of conveying your feelings to me, Sans. I’ve never once doubted your love for me. However, I’d be more than happy to teach you how to kiss. Even without lips, I’m sure your kisses would be just as magnificent as you.”

A large grin forms on his face as his expression brightens. “THAT’S RIGHT! BECAUSE I AM AMAZING AT ANYTHING I TRY! NOTHING IS IMPOSSIBLE FOR THE MAGNIFICENT SANS!”

With a nod, you shove your phone back into your pocket and turn to face him on the bed. When you cup his cheeks and gently stroke them with your thumbs, Sans immediately leans into your touch which makes you smile. “Okay, the first thing you need to know is you should always close your eyes when you’re kissing. Most people find it awkward to be stared at when they’re kissing someone.”

His eyes quickly fall shut which makes you grin in amusement. When you bring your mouth closer to his, your breath fans out against his teeth which makes him shiver. “The rest will have to be taught by example. Just remember that it’s all about showing the person how much you care about them. That’s all that matters. You don’t have to be an amazing kisser right from the start. As long as you put your honest feelings into the kiss, then it’ll always be a great one.”

With that, you ignore the hard thumping of your rapidly beating heart and press your mouth against his. You feel a slight shock as soon as your lips make contact with his teeth. It doesn’t hurt, however. Rather, it causes your lips to pleasantly tingle.

It doesn’t take long for Sans to mimic your actions as he moves his mouth against yours. While you wrap your arms around his neck to pull him closer, the skeleton cups your cheeks and strokes them with a tenderness that makes you clutch him tighter in response.

When you pull away, you see his whole face is glowing a dark blue. His eye-lights have turned into little blue hearts as he dazedly stares at you while wearing a big, dopey grin. 

Just when you didn’t think it was possible for your boyfriend to get any cuter, he shows you that adorable expression. Without hesitation, you pull the skeleton into your lap and start showering him in kisses, making sure that not an inch of his face goes untouched by your lips.

“MWEH HEH HEH.”

All the while, Sans giggles at your ministrations, and his blush grows even darker which makes him resemble a blue neon sign. You hug him tighter in response to his adorable reaction.

Once you’re satisfied, you finally end your kiss attack and move to affectionately nuzzle his cheek. “See? Lips aren’t necessary for a good kiss. After receiving a kiss like that, I think I much prefer skeleton kisses.”

Sans beams at your words, obviously happy that you enjoyed the kiss. “OF COURSE, YOU WOULD! AFTER RECEIVING A KISS FROM ME, ANY OTHER KISS OBVIOUSLY PALES IN COMPARISON!”

He then tilts his head curiously. “ACCORDING TO MY RESEARCH, THERE’S ANOTHER WAY TO KISS THAT HUMANS PARTICULARLY ENJOY. COULD YOU TEACH ME THAT AS WELL, Y/N?”

Your eyes widen in surprise. He couldn’t be talking about french kissing, could he? What kind of research has he been doing?! 

You feel your face heat up at the thought. While you have no problem with teaching him, you can’t help but feel a little flustered by the suggestion. Still, there’s no way you can turn him down when he’s looking at you so earnestly.

When you nod your head, his face brightens, and he gives you one of his sweet smiles which always makes your heart melt. You should probably provide some form of explanation, so he’ll know what to expect. “The kissing you’re probably talking about involves using your tongue. Despite being a skeleton, you have one of those, don’t you? I remember once seeing you stick yours out at your brother.”

“I HAVE ONE!”

Sans sticks his tongue out briefly to show you which makes you smile. He does it so cutely like when a cat bleps. You have to resist the urge to squeal and cuddle him.

“Okay. Like before, it’ll be better to show you through example. Just remember to part your teeth a little after I start kissing you, alright?”

At his nod, you bring your face closer to his. It’s good that you still have him in your lap; this position makes it a lot easier to kiss him. 

His eyes fall shut at the same time as yours when you press your mouth against his. Just like last time, your lips begin to tingle thanks to his magic. 

When Sans parts his teeth, you immediately slip your tongue inside and begin to explore the cavern of his mouth. You decide to take your time by slowly stroking every area that your tongue comes across.

He moans into the kiss as a result of your ministrations, and you find yourself deepening the kiss in response, tilting his head back as you plunge your tongue further inside.

You had honestly expected his kisses to taste like tacos considering how much he eats them. However, you are surprised when a minty flavor hits your tastebuds. Sans must’ve brushed his teeth recently; that would explain why he tastes like toothpaste. It probably shouldn’t come as such a surprise considering how highly he values personal hygiene. 

Sans clutches the front of your shirt with his hands in an attempt to pull you closer, and you quickly oblige by pressing your body further against his. You gently caress his cheek with one hand while your other arm wraps tightly around him and pulls him closer. 

His tongue brushes against yours, and you involuntarily shiver when you make contact with his magic. You waste no time in entwining your tongue with his which elicits a moan from both of you.

The tingling sensation caused by contact with his tongue is much more charged than from when you kissed his teeth. It gives you a pleasant shock that travels from your head down to your now curling toes. The longer your tongue remains in contact with his, the more charged his magic becomes.

Unfortunately, you have to end the kiss since your lungs are beginning to burn from lack of air. When you try to pull away, Sans whimpers in protest and clutches onto you tighter which makes you temporarily freeze.

You gently stroke his cheek with your thumb and caress his tongue with yours one last time before completely pulling away. However, you let your mouth remain a few inches above his. Panting heavily, your breath hits his teeth, and he trembles in response. “Sorry, I didn’t want to stop, but I can only kiss for so long before I need to breathe.”

Seeing the worried look he aims your way, you smile and plant a chaste kiss on his teeth. “I’m alright. It’s just something all humans have to deal with when kissing. I’m kinda jealous of your lack of lungs. You could go on kissing forever since you don’t have to worry about breathing.”

As you sit up, Sans clambers out of your lap and moves to sit beside you again. He then grins at you. “WHILE I WOULD LOVE TO KISS YOU THAT LONG, I ALSO DON’T MIND DOING IT THIS WAY. I THINK MULTIPLE SHORT KISSES WOULD BE MORE ENJOYABLE THAN ONE LONG ONE ANYWAY!”

Leave it to Sans to find the bright side of things. You grin in amusement. Before you can respond, his grin suddenly turns mischievous. 

In a blink, you find yourself pushed down against the mattress with Sans hovering above you. His hands hit the bed with your head resting in between them. 

Your eyes widen when you see the smirk on your boyfriend’s face. It’s your first time seeing such an expression on his face. You can feel your heart start to beat rapidly as he leans closer to you. 

“SINCE YOU WERE KIND ENOUGH TO TEACH ME, IT’S ONLY FAIR THAT I REWARD YOU BY SHOWING YOU THE FRUITS OF YOUR EFFORTS. DON’T YOU AGREE?”

A blush covers your cheeks as he speaks those words after coming to a halt with his face a few inches above yours. Looks like there’s more than meets the eye when it comes to Sans. While you knew that he wasn’t always as innocent as everyone perceives him to be, you didn’t know he had this side to him. You can’t help but feel a thrill of excitement at the sudden change in events. 

Rather than respond, you simply wrap your arms around his neck and bring him down to close the remaining distance between you. You part your lips for him, and he immediately slides his tongue inside your mouth.

Similar to how you kissed him, Sans starts by exploring the cavern of your mouth and tenderly caressing those areas with his tongue. When his tongue strokes a particular spot, you moan into the kiss and clutch him tighter which makes him grin into the kiss. 

He uses one of his hands to cup your cheek as he deepens the kiss. You dig your fingers into the vertebrae of his neck and pull him closer which elicits a groan from him. 

While the last kiss gave you a shock, this one leaves your whole mouth feeling electrified. It’s like the charge of his magic has doubled. You tremble at the sensation as his tongue entwines with yours. 

Just as your lungs start to burn from lack of air, Sans pulls away to end the kiss. Despite his hooded eyes, you can still easily make out his now heart-shaped eye-lights which are lovingly watching you. Seeing that along with his brightly glowing cheeks makes you smile.

The two of you are breathing heavily now as you both attempt to catch your breath. After a few seconds pass, Sans lets his body fall on top of yours, and you quickly wrap your arms around him in a warm hug which he instantly reciprocates.

With a happy sigh, the skeleton nuzzles his face against your chest. “I THINK THAT LESSON WENT VERY WELL, DON’T YOU? OF COURSE, I AM NOT FOOLISH ENOUGH TO THINK THAT JUST ONE LESSON IS ENOUGH. IT’S IMPORTANT TO PRACTICE REGULARLY SO THAT YOU KNOW FOR SURE THAT YOU HAVE EVERYTHING DOWN. I AM LOOKING FORWARD TO THE NEXT LESSON, Y/N.”

You can’t help but giggle at his words as you give him a warm squeeze. Your boyfriend sure can be sly sometimes. Well, it’s not like you have any problems with this plan. You’re looking forward to the next lesson just as much as he is.

How could you not when you have such a good student?

**Author's Note:**

> Once again, I write another practically plot-less oneshot just cause I wanna smooch a skeleton lol Blueberry is like my fav skeleton, yet till now I hadn't written any one-on-one interactions with him in a oneshot despite my great love for him. I was very disappointed in myself when I realized this lol So, that's how this little oneshot was born. It's not much, but my main goal in this was to smooch Blue so mission accomplished XD 
> 
> Were y'all surprised by his change in demeanor at the end? While I do see Blue as one of the most innocent Sanses, I still see him as having a mischievous side. It's hard for me to see any Sanses as completely pure lol XD
> 
> Hope you enjoyed the fic! ^-^


End file.
